The present invention relates to access to an external storage device of a computer.
While hard disk drives have been widely used to date as external storage devices for computers, more recently, SSD (Solid State Drives) are starting to come into use as well.
With an SSD, when large numbers of small files are being overwritten, processing time can sometimes be considerable due to a phenomenon known as “stutter”. This is due to the fact that SSDs use flash memory as storage elements. Typically, with a flash memory, it is not possible to overwrite a block only partially. When an SSD overwrites data, data of all pages of the block that includes the page being overwritten and not being overwritten are deleted, and subsequently data of all of the pages are written to the block; stuttering occurs during this time. For this reason, conventional technologies setting up a cache memory area for SSD in the main memory of the computer have been adopted in the past. With the conventional technologies, however, because the cache memory area set up in the main memory is managed by the computer's OS, it is possible that lower access speeds to the SSD may be associated with such management by the OS. Accordingly, there exists a need to prevent the lower access speeds associated with conventional management of cache memory by the OS, and to speed up the perceived speed of access to SSD. Similarly, there exists a need to speed up the perceived speed of access to memory devices other than SDD as well. For example, in the case of a hard disk unit, if a single file is written in segments, the write time may be considerable due to the need for considerable travel of the head.